Protective device



H. G. FRENCH.

PROTECTIVE DEVICE.

APPLICATION FILED 00124, m9.

Patented June 28, 1921.

Inventofem? 6. French His Attorney.

UNITED STATES PATENT OFFICE.

HENRY G. FRENCH, or SCHENECTADY N EW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A conroaarron or NEW YORK.

- PROTECTIVE DEVICE.

Specification of Letters Patent. P t t J 2 9 "Application filed October 24, 1919. Serial No. 333,019.

To all whom it may concern: 1 V

Be it known that I, HENR G. FRENCH, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Protective Devices, of which the following is a specification.

My inventionrelates to protective devices particularly to relays and has for its object to provide a relay which in response to,

' a predetermined abnormal condition will have a definite and positive pick up, which will move positively to contact controlling position, which has a quick return and which embodies other features to be described more in detail hereinafter.

In relays of the induction type in which a rotatable armature is controlled by torque and counter torque elements, the counter torque element increases its effect as the armature is rotated in response to the torque element so that to obtain positive action it is necessary to provide means to compensate for the increase of counter torque. ithout compensation, the armature is not moved positively to contact controlling position on overload occurs before the armature has had time to reset or reach its initial position, the armature is again moved from some 1ntermediate position and the relay operates with the wrong time delay.

According to my invention I provide a relay which overcomes these undesirable features and which is a positive pick up, positive acting-and quick return device. In this relay, instead of increasing the driving torque to compensate for the increase of countertorque or increasing the driving torque sufliciently for it to predominate, I provide means whereby the driving torque predominates by decreasing or eliminating; the countertorque. When the abnormal conditlon has ceased, the countertorque, is a'uto-' matically increased or restored so that it. then predominates to effect a quick return.

of the relay to its initial position.

The novel features whichI believe to be. characteristic of my invention will be .dcjfi-; appended nitely indicated in the claims hereto; while the featuresof construction and mode of operation will be understood by reference to the following description taken in connection with the accompanying drawing in which Flgure 1 shows, in perspective, a relay embodying my invention and Fig. 2 shows, in

ing a modified form of my invention.

In Flg. 1 I have shown my invention em bodied in a relay of the induction type comprising a'rotatable armature memberl, carperspective, another type of relay embody ried by ashaft 2 and provided with permanent or drag magnets 3. Cooperating with armature 1 is an electro-magnetic driving or torque producing element 4: havin a magnetic frame 5 and windlngs 6 and I r 's 0,. thereon connected through transformer 8 to the cirr cuit to be protected. Connected to the shaft 2 is a restraining or countertorque element 9 of opposlte torque effect to that of the motor element 4. The shaft carries a movable contact arm 10 which is movable into and out of engagement with cooperating fixed contacts 11 to control an auxiliary or tripping circuit,,not shown. Under normal conditions the effect of the countertorque or restraining element 9 predominates to hold the contact arm 10 against a stop 12.,

For controlling the amount of countertorque exerted by the restralnlng means or spring 9, I provide a means automatically "operative in response to abnormal conditions to vary the tension of the spring or the f counter torque exerted thereby. This countertorque control means comprises a solenoid 13 having its winding in series with one of the windings of the motor element 4;, for instance, winding 6. The plunger of the solenoid 13 is connected through a' bell crank arm 14 and rod 15 to an arm 16 which is rotatably supported and to which is con-"- nected one end of the spring or restraining element 9. Tolimit the movement of hell crank 14 and thus limit the amount of decrease in tension which can be made on the spring 9, an adjustable stop 17 is provided. The solenoid is so wound that under normal conditions, it is not energized suiliciently to be operative.

The countertorque element 9 predominates until abnormal conditions occur above a predetermined amount upon the circuit to be protected. When the current from transformer 8 supplied to the windings 6 and 7 of the motor element produces a flux great enough so that the torque of the motor element 4 overcomes the countertorque of spring 9, the armature 1 and shaft 2 then starts to rotate in contact closing direction. Simultaneously with the increase of torque by the motor element t the countertorque controlling means is rendered operative and solenoid 13 is energized and attracts its plunger, rotating bell crank 14: and pulling rod 15. This operation moves arm 16 1n a direction to un wind the spring 9 and hence reduce its ten sion or countertorque by an amount requisite to maintain the driving torque exerted by the motor element 4 in predominance or, if desired, may remove entirely the effect of countertorque element 9. Instead, therefore, of increasing the effect of the motor element to compensate for the increased effect of the restraining means, I provide means whereby the effect of the driving element predominates by decreasing or eliminating the effect of the countertorque element. Upon the initial impulse or pick up of the armature, due to the predomlnating driving torque, the countertorque is practically simultaneously reduced so that the armature 1 and contact 10 is carried positively through its complete movement into contact closing direction upon that current through the motor element 4 or that driving tor ue required to initially start the armature. pon the cessation of the abnormal condition, it is necessary to increase or restore the effect of the countertorque element so that it will overcome the driving torque and return the armature to its initial position quickly. This is accomplished by the deenergization of the countertorque controlling means or solenoid 13 such that arm 15 and arm 16 are moved to quickly tension spring 9 which immediately exerts sufficient countertorque to overcome the reduced driving torque and return the armature to initial position ready for the next operation.

In Fig. 2 I have shown a modified form of my invention applied to an induction relay of the reverse power type. In this type of relay it is essential that the armature with the contact carrying arm be moved to contact controlling position and returned to initial position. The relay shown in Fig. 2 is the usual type of polyphase induction type, reverse power relay, having two armatures 18 and 19 carried by and acting on the shaft 20. The lower armature 19 is controlled by two motor or driving torque elements 21 and 22 adapted to be connected to corresponding phases of the circuit to be protected while the motor element 23, corresponding to the third phase, produces a driving torque on the upper armature 18. The shaft 20 carries the usual contact 2& movable into and out of engagement with a cooperatingfixed contact 25.

he countertorque element comprises a spring or restraining means 26 the tension or countertorque of which is controlled by a countertorque controlling means. This controlling means consists of an induction or armature member 27, which is shown as a disk segment pivotally mounted at one end to a support 28, and which is rotatable between the shaded poles of an electromagnetic or motor element 29. The countertorque or spring member 26 is secured at one end to the armature 27 of the control device by means of stud 30 and is secured at the other end to a stud 31 on the upper armature 18. Another restraining means or spring 32 is connected at one end to stud 33 carried by the armature segment 27 and at the other end to the fixed support 28. The motor element 29 receives flux by means of a winding 34 which is in series with one of the current windings of the motor elements 21, 22 or 23.

The springs 26 and 32 are arranged to exert opposing torques on the armature segment 27 but normally spring 32 predominates. The counter-torque exerted by spring 26 normally overcomes the driving torque exerted by the motor elements 21, 22 and 23 to hold the armature 18 against a stop 35. Upon occurrence of an abnormal condition, such as a reversal of power, on the line to be protected, the torque exerted by one or more of the motor elements 21, 22 and 23 overcomes the countertorque exerted by spring 26 and moves the armatures 18 and 19 with shaft 20 and contact 24 in contact closing direction. Simultaneously the countertorque control device operates to eliminate or decrease the effect of countertorque element 26. The current in coil or winding 34 of motor element 29 is increased and exerts a torque on armature segment 27 to move it in a direction to decrease or eliminate entirely the tension of spring 26 and hence the effect of the counter torque element on the relay. The countertorque controlling means is thus operative in response to that abnormal condition necessary to operate the relay, to render the countertorque element ineffective. As the armature segment is moved to decrease or remove the tension of sprin 26, it increases, at the same time, the tens1on of spring 32. The torque, however, exerted by motor element 29 predominates. The armature 18 with armature 19, therefore moves contact 24 positively and quickly into engagement with contact 25 in response to the driving torque exerted by the motor elements 21, 22 or 23 and practically no eountertorque is exerted by spring 26 as the countertorque controlling device operates to eliminate its effect. a

In the countertorque control device, the

driving torque exerted by motor element 29' overcomes the countertorque of spring 32 to secure the desired effecton spring 26.

When normal conditions exist on the circuit to be protected, the driving torque of motor elements 21, 22, and 23, diminish and it is essential that the countertorque element then functions to reurn the relay to its initial position. When normal 'condi- I tions exist the effect of winding 34 of tertorque controlling device thus operates in response to the abnormal conditions to remove the effect of thecountertorque element 26 and upon disappearance of the abnormal conditions to render said countertorque element operative to return the relay to its initial position. The relay operates therefore in contact controlling direction with substantially no opposing or countertorque whereupon the disappearance of the abnormal condition, the effect of the countertorq'ue element is restored and it operates to quickly return the relay to its initial position.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a relay device, the combination with a movable armature member, a torque producing element for moving said armature in one direction, a counter-torque producing means for normally overcoming the effect of said torque producing element, and means operative under predetermined abnormal conditions for reducing the effect of said counter-torque element to enable said torque element to overcome said counter-torque element, said means acting to restore the effect of said counter torque element upon the return of normal conditions whereby said counter-torque element overcomes said torque element.

2. In a relay device of the induction type, a rotatable armature, contacts controlled thereby, restraining means exerting a force tending to hold said armature in its initial position and to quickly return said armature to said position, a motor element operative to overcome said restraining means and rotate said armature into contact controlling position, and means operative in response to predetermined abnormal conditions for ter torque element, and means for reducing reducing the force exerted by said restraining means toenable said motor element to positively overcome said restraining means and -move said armature to contact controlling position I 1 Q An induction type'relay comprising a rotatable armature member, contacts controlled by said armature, an electromagnetic driving element, a restraining element, said elements controlling the rotation of said armature, and means operative in response to. abnormal conditions of predetermined amount for reducing the effect of said .restraining element to permit said driving member to positively rotate said'armature into contact closing position and operative when said abnormal conditions are below. said predetermined. amount to cause said restraining elementto overcome said driving member and return said armature to initial position.

4:. In a relay device having a rotatable armature, a torque element andra countertorque element cooperating to control the rotation of said armature, said counter-torque element predominating until predeterminedv abnormal conditions occurwhensaid torque element predominates to rotate said arma-i ture'against the-force exerted by said counthe effect of said counter torque element so that the torque necessary to initially overcome said counter-torque element'is sufficientto carry said armature throughout its com-- pletelpath of travel.

5. n a. relay device, the combination with a rotatable armature, contacts controlled thereby, of an electro-magnetic driving element for rotating said armature in contact controlling direction, restraining means overcoming the effect of said driving element until the occurrence of predetermined abnormal condition, and an electromagnetic device operative in response to said predetermined abnormal conditions for reducing the effect of said restraining means to enable the effect of said driving element to predominate as long as said abnormal conditions exist.

6. In a relay device, the combination with a rotatable armature, contacts controlled thereby, of a torque element for rotating said armature in contact controlling direction, a spring normally overcoming the effect of said torque element but rendered ineffective upon abnormal conditions above a predetermined ampunt, and means for reducing the effect of said spring in response to the occurrence of said abnormal conditions to permit said torque element to predominate but operative in response to the return of normal conditions to overcome the effect of said spring whereby it returns said armature quickly to initial position.

7. In a relay device, the combination with a rotatable armature, contacts controlled thereby, a restraining element normally effective to hold said armature in initial position, a torque element acting to overcome said restraining element in response to predetermined abnormal conditions, and means operative to eliminate the effect of said restraining element upon the occurrence of said abnormal conditions to enable said armature to be moved free of restraint to contact controlling position.

8. In a relay device, the combination with a rotatable armature, contacts controlled thereby, a restraining element and a torque element cooperating to control the rotation of said armature, said restraining element normally predominatin and means operative in response to pre etermined abnormal conditions for removing the effect of said restraining element to permit said torque element to move said armature freely to.

contact controlling position, and means operative upon the return of normal conditions to increase the effect of said restraining element to return said armature quickly to initial position.

9. In a relay device, the combination with a rotatable armature, contacts controlled thereby, a restraining element for holding said armature in initial position, a torque producing means operative in response to reversal of power to overcome said restraining element and move said armature to contact controlling position, and means for eliminating the effect of said restraining quickly return said armature to initial position when conditions are normal.

10. In a relay device, the combination with a rotatable armature, contacts controlled thereby, a restraining element for holding said armature in initial position, a torque producing means operative in response to reversal of power to overcome said restraining element and move said armature to contact controlling position, and means for rendering said restraining element inoperative upon the occurrence of a reversal of power but operative to return said armature quickly to initial position when conditions become normal.

11. In a device of the class described the combination with a rotatable armature, contacts controlled thereby, an electromagnetic torque producing element adapted to be connected in circuit to produce a torque in said armature, a torque element arranged to produce a torque counter to the torque produced by said electromagnetic torque producing element, and electromagnetic means connected in circuit with said electromagnetic torque producing element to vary the action. of said counter torque element.

In witness whereof, I have hereunto set my hand this 23rd day of October, 1919.

HENRY G. FRENCH. 

